Lepton Physics

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Lepton Physics One of the four pillars: Tera-Z, Oku-W, Mega-H, John Ellis M = 246.0 ± 0.8 GeV, ε = 0.0000 +0.0015 -0.0010

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M = 246.0 ± 0.8 GeV, ε = 0.0000 +0.0015 -0.0010 . Lepton Physics. One of the four pillars: Tera -Z, Oku-W, Mega-H, Mega-t . John Ellis. Projected e + e - Colliders: Luminosity vs Energy. TLEP physics study group: arXiv:1308.6176. Global Analysis of Higgs-like Models. - PowerPoint PPT Presentation

Transcript of Lepton Physics

Page 1: Lepton Physics

Lepton Physics

One of the four pillars:Tera-Z, Oku-W, Mega-H, Mega-t

John Ellis

M = 246.0 ± 0.8 GeV, ε = 0.0000+0.0015-0.0010

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Projected e+e- Colliders:Luminosity vs Energy

TLEP physics study group: arXiv:1308.6176

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Global Analysis of Higgs-like Models• Rescale couplings: to bosons by a, to fermions by c

• Standard Model: a = c = 1JE & Tevong You, arXiv:1303.3879

b bbarτ τγ γW WZ ZGlobal

No evidence fordeviation from SM

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It Walks and Quacks like a Higgs• Do couplings scale ~ mass? With scale = v?

• Red line = SM, dashed line = best fitJE & Tevong You, arXiv:1303.3879

Globalfit

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What Next: A Higgs Factory?

To study the ‘Higgs’ in detail:• The LHC

– Consider LHC upgrades in this perspective• A linear collider?

– ILC up to 500 GeV– CLIC up to 3 TeV

(Larger cross section at higher energies)• A circular e+e- collider?• An ep collider?• A γγ collider? A muon collider?• Wait for results from LHC @ 13/14 TeV

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Possible High-Luminosity LHC Measurements

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Possible Future Higgs Measurements

Janot

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H Coupling Measurements Now@TLEPM = 246.0 ± 0.8 GeV, ε = 0.0000+0.0015

-0.0010

JE & Tevong You

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Indirect Sensitivity to 3h Coupling

• Loop corrections to σ(H+Z):

• 3h correction δh energy-dependent• δZ energy-independent: can distinguish

McCullough

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• Predictions of current best fits in simple SUSY models

• Current uncertainties in SM calculations [LHC Higgs WG]

• Comparisons with– LHC– HL-LHC– ILC– TLEP (= FCC-ee)(Able to distinguish from SM)

Impact of Higgs Measurements

K. De Vries(MasterCode)

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Possible FCC-ee Precision Measurements

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TLEP Measurements of mt & MW

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Theoretical Constraints on Higgs Mass

• Large Mh → large self-coupling → blow up at low-energy scale Λ due to renormalization

• Small: renormalization due to t quark drives quartic coupling < 0at some scale Λ→ vacuum unstable

• Vacuum could be stabilized by SupersymmetryDegrassi, Di Vita, Elias-Miro, Giudice, Isodori & Strumia, arXiv:1205.6497

Instability @1010 – 1013 GeV

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Vacuum Instability in the Standard Model • Very sensitive to mt as well as MH

• Instability scale:

• Calculate with accuracy ± 0.1

Buttazzo, Degrassi, Giardino, Giudice, Sala, Salvio & Strumia, arXiv:1307.3536

FCC-ee accuracy

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Sensitivity to Higher-Dimensional Operators

Possible new physics corrections to SM:

• LEP constraints• FCC-ee constraints• See Λ ~ 100 TeV?

JE, Sanz & You

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What else is there?

Supersymmetry• Successful prediction for Higgs mass

– Should be < 130 GeV in simple models• Successful predictions for couplings

– Should be within few % of SM values• Naturalness, GUTs, string, … (???)

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Data

• Electroweak precision observables

• Flavour physics observables

• gμ - 2• Higgs mass• Dark matter• LHCMasterCode: O.Buchmueller, JE et al.

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Search with ~ 20/fb @ 8 TeV

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p-value of simple models ~ 5% (also SM)

2012 20/fb

Scan of CMSSM

Buchmueller, JE et al: arXiv:1312.5250

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Confronted with likelihood analysis of CMSSM

LHC Reach for Supersymmetry

K. De Vries(MasterCode)

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Confronted with likelihood analysis of CMSSM

Direct Reach for Supersymmetry

Stau mass contours

500 GeV(ILC1000)

1500 GeV(CLIC)

TLEP, ILC500have no impact

K. De Vries(MasterCode)

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ΓZ constraint on (m0, m1/2) plane in CMSSM:All points within one current σ of low-mass best-fit value

Impact of LEP Precision on Susy

K. De Vries(MasterCode)

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ΓZ constraint on (m0, m1/2) plane in CMSSM:Points within one, two, three TLEP σ of low-mass best-fit value

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

ΓZ

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MW constraint on (m0, m1/2) plane in CMSSM:All points within one current σ of low-mass best-fit value

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

MW

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Estimate of (m0, m1/2) in CMSSM on basis ofprecision measurements with low-mass best-fit central values

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

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One-dimensional likelihood functions in CMSSM ifprecision measurements with low-mass best-fit central values:

compare masses with LHC measurements,

Test SUSY at the loop level

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

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Assume no SUSY @ HL-LHC:current precision measurements with high-mass best-fit values

Impact of HL-LHC on Susy

K. De Vries(MasterCode)

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One-dimensional likelihood functions in CMSSM ifprecision measurements with high-mass best-fit central values:

Predict masses for FCC-pp measurements

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

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The Twin Frontiers of FCC-ee Physics

Precision Measurements • Springboard for

sensitivity to new physics

• Theoretical issues:– Higher-order QCD– Higher-order EW– Mixed QCD + EW

• Experimental issues– Gigi Rolandi

Rare Decays• Direct searches for new

physics• Many opportunities• Z: 1012

• b, c, τ: 1011

• W: 108

• H: 106

• t: 106

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cf, LEP and LHC• “Those who don't know history are doomed

to repeat it…”–Edmund Burke

• “… and maybe also those who do.”• LEP: Precision Z studies, W+W-,

search for Higgs, anything else• LHC: search for Higgs, anything else• FCC-ee, -pp together: 50 years of physics

✔ ✔✖ ✖

✔ ?

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O. Buchmueller, R. Cavanaugh, M. Citron, A. De Roeck, M.J. Dolan, J.E., H. Flacher, S. Heinemeyer, G. Isidori, J. Marrouche, D. Martinez Santos, S. Nakach, K.A. Olive, S. Rogerson, F.J. Ronga, K.J. de Vries, G. Weiglein

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July 4th 2012The discovery of a

new particle

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Possible Future Higgs Measurements

• Need to reduce theoretical uncertainties to match• Essential for new physics interpretations

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Impact of TLEP Precision on SusyMW constraint on stop mass sin2θW constraint on stop mass

V. SanzTLEP physics study group: arXiv:1308.6176

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Rl constraint on (m0, m1/2) plane in CMSSMPoints within one, two, three TLEP σ of low-mass best-fit value

Impact of FCC-ee Precision on Susy

K. De Vries(MasterCode)

Rl